# Java - Format integer as base 8 and base-16

## Introduction

When conversions 'o' and 'x' are used with a negative argument of byte, Byte, short, Short, int, Integer, long, and Long data types, the argument value is converted to an unsigned number by adding a number 2N to it, where N is the number of bits used to represent the value of the data type of the argument.

For example, if the argument data type is byte, which takes 8 bits to store the value, the argument value of -X will be converted to a positive value of -X + 256 by adding 256 to it and the result contain the base-8 or base-16 equivalent of the value -X + 256.

The conversions 'o' and 'x' do not transform the negative argument value to an unsigned value for a BigInteger argument type.

Consider the following code:

## Demo

```public class Main {
public static void main(String[] args) {
byte b1 = 9;/*from  w  w w  .  java 2 s .co  m*/
byte b2 = -9;
System.out.printf("%o %n", b1);
System.out.printf("%o %n", b2);
}
}
```

## Result

The conversion 'o' outputs the base-8 integer 11 for a positive decimal integer 9.

However, when a negative decimal integer -9 is used with the 'o' conversion, -9 is converted to a positive number -9 + 256 (=247).

The final output contains 367, which is the base-8 equivalent of the decimal 247.

The following code shows some more examples of 'o' and 'x' conversions for int and BigInteger argument types:

## Demo

```import java.math.BigInteger;

public class Main {
public static void main(String[] args) {
System.out.printf("%o %n", 2028);
System.out.printf("%o %n", -2028);
System.out.printf("%o %n", new BigInteger("2028"));
System.out.printf("%o %n", new BigInteger("-2028"));

System.out.printf("%x %n", 2028);
System.out.printf("%x %n", -2028);
System.out.printf("%x %n", new BigInteger("2028"));
System.out.printf("%x %n", new BigInteger("-2028"));

System.out.printf("%#o %n", 2028);
System.out.printf("%#x %n", 2028);
System.out.printf("%#o %n", new BigInteger("2028"));
System.out.printf("%#x %n", new BigInteger("2028"));
}/*  w w  w.j  a v  a  2s.  c  om*/
}
```

## Locale

Many locale-specific formatting are automatically applied when a numeric value is formatted.

The following code shows the same number 1234567890 formatted differently for three different locales US, Indian, and Thailand:

## Demo

```import java.util.Locale;

public class Main {
public static void main(String[] args) {
Locale englishUS = new Locale("en", "US");
Locale hindiIndia = new Locale("hi", "IN");
Locale thaiThailand = new Locale("th", "TH", "TH");
System.out.printf(englishUS, "%d %n", 1234567890);
System.out.printf(hindiIndia, "%d %n", 1234567890);
System.out.printf(thaiThailand, "%d %n", 1234567890);

}//from w  w  w . j a va  2  s  . c o  m
}
```